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Erythema multiforme

Erythema multiforme (EM) is an acute skin reaction that comes from an infection or another trigger. EM is a self-limiting disease. This means it usually resolves on its own without treatment.

Causes

EM is a type of allergic reaction. In most cases, it occurs in response to an infection. In rare cases, it is caused by certain medicines or body-wide (systemic) illness.

Infections that may lead to EM include:

Medicines that may cause EM include:

  • NSAIDs
  • Allopurinol (treats gout)
  • Certain antibiotics, such as sulfonamides and aminopenicillins
  • Anti-seizure medicines

Systemic illnesses that are associated with EM include:

EM occurs mostly in adults 20 to 40 years old. People with EM may have family members who have had EM as well.

Symptoms

Symptoms of EM include:

Skin sores may:

  • Start quickly
  • Come back
  • Spread
  • Be raised or discolored
  • Look like hives
  • Have a central sore surrounded by pale red rings, also called a target, iris, or bulls-eye
  • Have liquid-filled bumps or blisters of various sizes
  • Be located on the upper body, legs, arms, palms, hands, or feet
  • Include the face or lips
  • Appear evenly on both sides of the body (symmetrical)

Other symptoms may include:

There are two forms of EM:

  • EM minor usually involves the skin and sometimes mouth sores.
  • EM major often starts with a fever and joint aches. Besides the skin sores and mouth sores, there may be sores in the eyes, genitals, lung airways, or gut.

Exams and Tests

Your health care provider will look at your skin to diagnose EM. You'll be asked about your medical history, such as recent infections or medicines you've taken.

Tests may include:

Treatment

EM usually goes away on its own with or without treatment.

Your provider will have you stop taking any medicines that may be causing the problem. But, don't stop taking medicines on your own without talking to your provider first.

Treatment may include:

  • Medicines, such as antihistamines, to control itching
  • Moist compresses applied to the skin
  • Pain medicines to reduce fever and discomfort
  • Mouthwashes to ease discomfort of mouth sores that interferes with eating and drinking
  • Antibiotics for skin infections
  • Corticosteroids to control inflammation
  • Medicines for eye symptoms

Good hygiene may help prevent secondary infections (infections that occur from treating the first infection).

Use of sunscreen, protective clothing, and avoiding excessive exposure to sun may prevent the recurrence of EM.

Outlook (Prognosis)

Mild forms of EM usually get better in 2 to 6 weeks, but the problem may return.

Possible Complications

Complications of EM may include:

  • Patchy skin color
  • Return of EM, especially with HSV infection

When to Contact a Medical Professional

Call your provider right away if you have symptoms of EM.

Alternative Names

EM; Erythema multiforme minor; Erythema multiforme major; Erythema multiforme minor - erythema multiforme von Hebra; Acute bullous disorder - erythema multiforme; Herpes simplex - erythema multiforme

References

Holland KE, Soung PJ. Acquired rashes in the older child. In: Kleigman RM, Lye PS, Bordini BJ, Toth H, Basel D, eds. Nelson Pediatric Symptom-Based Diagnosis. Philadelphia, PA: Elsevier; 2018:chap 48.

Rubenstein JB, Spektor T. Conjunctivitis: infectious and noninfectious. In: Yanoff M, Duker JS, eds. Ophthalmology. 5th ed. Philadelphia, PA: Elsevier; 2019:chap 4.6.

Shah KN. Urticaria and erythema multiforme. In: Long SS, Prober CG, Fischer M, eds. Principles and Practice of Pediatric Infectious Diseases. 5th ed. Philadelphia, PA: Elsevier; 2018:chap 72.

Review Date 10/14/2018

Updated by: Michael Lehrer, MD, Clinical Associate Professor, Department of Dermatology, University of Pennsylvania Medical Center, Philadelphia, PA. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.